Actuator lock mechanism



Oct. 29, 1957 E. H. HARTEL 2,811,137

ACTUATOR LOCK MECHANISM Filed Nov. 14, 1955 IN V EN TOR.

ERWIN H. HARTEL BY l Arron/vir United States Patent 2,811,137 ACTUATORLOCK MECHANISKM Erwin H. Hartel, Cleveland, Ohio, assignor to TheCleveland Pneumatic Tool Company, Cleveland, Ohio, a corporation of OhioApplication November 14, 1955, Serial No. 546,632 Claims. (Cl. 121-40)This invention relates to actuators in general and more particularly toa new and improved actuator lock mechanism adapted to lock the actuatorin one extreme position of its stroke.

It is an important object of this invention to provide an actuator lockmechanism which is light weight and dependable in operation.

It is another important object of this invention to provide acombination actuator and lock therefor which locks the actuator in oneextreme position of its stroke and which is released by the pressurefluid used to operate the actuator.

It is still another object of this invention to provide an actuatorincluding relatively movable piston and cylinder members wherein a lockplunger is mounted in the piston member for axial movement relativethereto in suchl a manner that the piston member is releasably locked inone extreme position of its stroke.

Further objects and advantages will appear from the followingdescription and drawings, wherein:

Figure 1 is a side elevation of an actuator incorporating a lockmechanism according to this invention;

Figure 2 is a side elevation in longitudinal section showing theactuator and lock structure with the elements in the locked position;

Figure 3 is a view similar to Figure 2 showing the position of theelements in the unlocked position; and,

Figure 4 is a fragmentary perspective View of the latch portion of thelock mechanism.

Referring to the drawings, an actuator incorporating a lock mechanismaccording to this invention is provided with a cylinder pivotallyconnected at one end as at 9 to a base or frame 11 and provided with apiston tube 12 extending from the other end. The piston tube 12 ispivotally connected to a load arm 13 by a trunnion member 14 in such amanner that axial movement of the piston tube rotates the load armaround a pivot 16 on the frame or base 11. The load arm 13 is providedwith a pivot bore 18 to which a load can be connected. The variouselements are shown in solid in Figure 1 with the piston tube 12 in theleft hand extreme position of its stroke, and in phantom with the pistontube in the right hand extreme position of its stroke. When the pistontube 12 moves between the two extreme positions, the load arm 13 rotatesaround the pivot 16 through an angle A.

Referring to Figures 2 and 3, the piston tube 12 is formed with a pistonhead 21 which moves along a cylinder wall 19 formed in the cylinder 10.'Ihe right or outer end of the piston tube 12 is supported by a glandmember 28 which is mounted in the right end of the cylinder 10 against ashoulder 29 by a gland nut 31. Thus the piston tube V12 is axiallymovable within the cylinder 10 between a left hand extreme positionwherein the left end of the piston tube 12 engages a radial wall 4t)formed in the cylinder 10 and a right hand extreme position wherein thepiston-head 21 engages a skirt portion 55 formed on the gland member 28.

The piston tube 12 is provided with a irst axial bore 22 and a secondlarger coaxial bore 24 through which a lock plunger 23 projects. Apiston head 26 formed 0n 2,81 1,13 7 VPatented Oct. 29, 1 957 the lockplunger 23 engages the wall of the second bore 24 to laterally supportthe left end of the lock plunger 23 while the right end thereof issupported by a bearing portion 27 formed in the piston tube 12. Thus thelock plunger 23 is carried by the piston tube 12 and is axially movablerelative thereto between a left hand extreme position wherein the leftend of the lock plunger 23 engages a radial wall 41 on a stop member 39which is threaded into the end of the piston tube 12 and a right handextreme position wherein the piston head 26 engages a shoulder 38between the two bores 22 and 24. The lock plunger 23 is normallymaintained in its left hand extreme position by a spring 42 whichextends between a collar 43 on the lock plunger 23 and a radial wall 44on the piston tube 12.

The gland member 28 is provided with a pair of seals 32 which preventfluid leakage out of the cylinder 10 and the piston heads 21 and 26 areprovided with uid seals 32a which prevent leakage of fluid past thepiston heads.v divided into two chambers 33 and 34 which are adapted toreceive pressure fluid. It should be understood that the chamber 33includes the zone around the piston tube to the left of the piston head21 as well as the zone within the bore 24 to the left of the piston head26. VFluid communication is provided between these two zones throughradial ports 36. Therefore pressure fluid in the chamber 33 produces anaxial force to the right on the piston head 26 as well as on the pistonhead 21. However, pressure lluid in the chamber 34 only produces ankaxial force on the piston head 21 because the piston head 26 is notexposed to pressure fluid in this chamber. Pressure lines 37 and 35provide a fluid connection between a source of pressure (not shown) andthe two chambers 33 and 34 respectively. A port 56 formed in the skirt55 to permit uid to flow freely between the pressure line 35 and thechamber 34. A suitable valve mechanism should be provided to selectivelyconnect one of the chambers 33 or 34 to the source of pressure uid andalso connect the other chamber to a reservoir return.

The frame or base 11 is provided with a pair of stationary pins 46 whichare parallel to the` axis of the actuator when it is locked. These pinsare proportioned to project through cooperating bores 47 formed in alatch member 48 which is in turn mounted on the end of the lock plunger23 by a cross pin 49. The various proportions are arranged so that theload arm 13 is inclined relative to the axis of the cylinder 10 when thepiston 12 is in the left hand extreme position. In other words, the linethrough the center of the pivot 16 and the trunnion member 14 intersectsthe axis of the piston 12 to form an angle B which is substantiallylargerV than Therefore, when the load arm 13 rotates from the left handextreme position, which is the locked position shown in solid in Figure1, to the phantom position, the initial movement of the piston tube 12is inclined relative to its axis so that there is initially a verticalor normal component of movement. The pins 46 provide surfaces parallelto the axis of said piston which are engaged by the walls of the bores47 and prevent such vertical or normal movement so long as they projectthrough the cooperating bores 47 formed in the latch member 48.Therefore, the load arm 13 cannot be rotated from the locked positionwhile the lock plunger is in the left hand or locked position. It shouldbe understood Vthat the spring 42 holds the lock plunger 23 in thisposition when pressure lluid is not supplied to the chamber 33. As soonas pressure fluid is supplied to' the chamber 33 through the pressureline 37, the lock' plunger 23 moves to the right against the force ofthe spring l42 until the vlatch member 48 moves clear of the pins 46. Atthis time the load armx13 can rotate in a clockwise direction'faro'undTherefore, the cavity within the cylinder 10 is the pivot 16 under theinuence of pressure lluid in the chamber 33. This movement will continueuntil the piston head 21 engages the stop skirt 55 formed on the glandmember 28 which limits its movement to the right.

When it is desired to operate the actuator to move the load arm 13 fromthe phantom position of Figure l back to the locked position, pressureiiuid is introduced into the chamber 34 and the piston 12 moves to theleft toward the position shown in Figure 2. The latch member 48 isprovided with a lower portion 51 which engages the ends of the pin 46 asthe piston approaches the locked position. This overcomes the force ofthe spring 42 and prevents the lock plunger 23 from moving axially withthe piston 12 as the latter continues to the lett. As soon as the pistonrod 12 has moved to the left extreme position, the pins 46 are alignedwith the cooperating bores 47 so that the force of the spring 42 canmove the lock plunger to the lett relative to the piston rod 12. Theelements then assume the position shown in Figure 2 at which time theactuator is again locked. A key 57 on the piston tube 12 projects intoan axial groove 58 on the lock plunger 23 and prevents relative rotationbetween the two members so that bores 47 will. always align with the pin46. Those skilled in the art will recognize that an actuator and lockaccording to this invention has many uses wherein the connected loadmust be mechanically locked in one position while being movable by theactuator to other positions.

Although a preferred embodiment of this invention is illustrated, itwill be realized that various modifications of the structural detailsmay be made without departing. from the mode of operation and theessence of the invention. Therefore, except insofar as they are claimedin the appended claims, structural details may be varied. widely withoutmodifying the mode of operation. Accordingly, the appended claims andnot the aforesaid detailed description are determinative of the scope ofthe invention.

I claim:

l. An actuator comprising cooperating piston and cylinder membersaxially movable relative to each other in response to pressure uid, aload on a base with one portion constrained to move in a predeterminedlocus, one of said members being connected to said base and the other tosaid one portion of said load, lock meansI carried by said other memberaxially movable relative thereto between a locked position and anunlocked position and movable from said locked position to said unlockedposition in response to said pressure uid, spring means biasing` saidlock means toward said locked position, and a latch engageable by saidlock means only when said lock means are in said locked position, saidpredetermined locus being inclined relative to the axis of said memberswhen said latch and lock means are engaged, said latch and lock meanspreventing movement of said lock means and other member along saidpredetermined locus upon said engagement.

2. An actuator comprising cooperating piston and cylinder membersaxially movable relative to each other in response to pressureI uid, aloadon a base with one portion constrained to move in a predeterminedlocus,- one of said members being connected to said base and the otherto said one portion of said load, lock means carried by said othermember axially movable relative thereto between a locked position and anunlocked posi-y tion and movable from said locked position to saidunlocked position in response to said pressure fluid, spring 3. Anactuator comprising a cylinder member, a piston member in said cylindermember cooperating therewith to dene a chamber adapted to receivepressure fluid and thereby produce relative axial motion between saidmembers from a iirst to a second relative position, a load on a basewith one portion constrained to move in a predetermined locus, one ofsaid members being connected to said base and the other to said oneposition of said load, lock means carried by said other member axiallymovable relative thereto from a locked position to an unlocked positionin response to pressure uid in said chamber, spring means biasing saidlock means toward said locked position, and a latch on said baseengageable by said lock means only when said lock means is in saidlocked position andk said members are in said rst position, saidpredetermined locus being inclined relative to the axis of said memberswhen said latch and lock means.

are engaged, said latch and lock means being proportioned to preventmovement ot said lock means and other member along said predeterminedlocus upon said engagement.

4. An actuator comprising a cylinder, a piston in said cylindercooperating therewith to define a chamber adapted to receive pressurefluid and thereby produces relative axial motion between said piston andcylinder from a irst to a second relative position, said piston beingformed with an axial passage, a lock plunger exposed to said chamberaxially movable in said passage between a locked and an unlockedposition, spring means normally maintaining said lock plunger in saidlocked position, said lock plunger being movable in response to saidpressure fluid to said'unlocked position, said cylinder being pivotallyconnected to a frame and said piston being pivotally connected to a loadarm which is in turn pivoted on said frame, the proportions beingarranged so that movement of said piston from said first positionrotates said load arm around its pivot on said frame and moves the pivotof said piston on said load `arm in a direction inclined relative to theaxis of said piston, latch means operably connected between said lockplunger and frame providing a surface parallel to the axis of saidpiston adapted to vprevent movement of said lock. plunger and in turnsaid piston in said inclined4 direction only when said piston is in saidfirst position and said lock plunger is in said locked position.

5. An actuator comprising a cylinder, a piston in said cylindercooperating therewith to define a chamber adapted to receive pressureiiuid and thereby produces relative axial motion between said piston andcylinder from. a rst to a second relative position, said piston being'formed with an axial. passage, a lock plunger exposed to said chamberaxially movable in said passage between a locked and an unlockedposition, spring means normally maintaining said lock plunger in saidlocked position, said lock plunger being movable' in response to saidpressure fluid to said unlocked position, said cylinder being pivotallyconnected to a frame and said piston being pivotally connected tol aload arm which is in turn pivoted on said frame, the proportions beingarranged so that movement of said piston from said first positionrotates said load arm around its pivot on said frame and moves the pivotof said piston on said load arm in a direction inclined relative tol theaxis of saidv piston, a latch member on said: lock plunger formed with abore parallel to the axis means biasing said lock means toward saidlocked position, and a latch engageable by said lock means only whenIsaid Ylock meansare in said locked position, said predetermined locusbeing inclined relative to the axis of said members when both said latchand lock means are engaged, said latch and lock means permittingmovement of saidlock means and otherv member only in a direction alongthe axis thereof upon said engagement.

of said piston, a stationary pin on said frame projecting into said.latch member bore only when said piston is in said iirst position andsaid lock plunger is in said lockedposition, said pin preventingmovement of said lock plunger and in turn said piston in said inclineddirection when it' projects into said latch member bore.

References cned in the sie of this parent FOREIGN PATENTS 577,947 iGreat Britain June 6, 1946

